(1) Field of the Invention
The present invention relates to an electric junction box to be mounted on a motor vehicle as a mobile unit.
(2) Description of the Related Art
Generally, a motor vehicle as a mobile unit mounts various electronic equipment, for example, a lamp such as a headlamp or tail lamp, a motor such as a starter motor or motor for an air conditioner, and so on.
In order to supply electric power to the various electronic equipment described above, the motor vehicle is provided with a junction block at an appropriate position of the vehicle. The junction block is formed by putting various electrical circuit units such as many fuses or relays together.
Since the junction block may include a fuse, relay or busbar, therefore the junction block may be called a fuse block, relay box or electric junction box as a generic term (for example, see Japanese Patent Application Laid-Open No. H10-241547 and Japanese Patent Application Laid-Open No. 2001-155618). Hereinafter, in this specification, a fuse block, relay box and junction block are called electric junction box as a generic term.
An electric junction box shown in Japanese Patent Application Laid-Open No. H10-241547 and Japanese Patent Application Laid-Open No. 2001-155618 includes a box body forming an external form of the electric junction box and a wiring block. The box body is made of electrically insulating synthetic resin and formed in a box-shape. The box body includes: a mounting section, on which electrical components such as a relay and fuse, and a power integration as an electric power distributing unit are mounted; and a connector fitting section, to which a connector of a wiring harness is fitted.
The wiring block is received in the box body. The wiring block includes: a first busbar to be connected to a battery as a first power source; a second busbar to be connected to an electric generator as a second power source; a fuse connecting the first busbar to the second busbar; and a connecting terminal.
Each of the first and second busbars is made of an electrically conductive sheet metal and includes: a power source connecting section to be connected to the battery or generator described above; and a terminal section, which is positioned within the mounting section when the wiring block is received in the box body, and is connected to the electrical components such as a relay or fuse and the power integration. A plurality of the terminal sections, each of which is connected to the electrical components such as a relay or fuse, are provided, while one terminal section, which is connected to the power integration, is provided.
The fuse connects a part of the first busbar to a part of the second busbar, each said part being located away from the power source connecting section. One part of the connecting terminal is positioned within the mounting section and connected to the electrical components such as a relay or fuse, while another part of the connecting terminal is positioned within the connector fitting section and connected to the connector of the wiring harness.
The power integration includes: a frame body made of electrically insulating synthetic resin and formed in a box-shape; a plurality of fuses attached to the frame body; a plurality of relays received within the frame body; and a busbar which electrically connects the fuses to the relays according to a predetermined pattern.
The busbar of the power integration includes: an electric power inputting section, which is connected to the terminal section of the first or second busbar through an electric wire and to which the electric power is supplied from the power source through the first or second busbar; and a plurality of electric power outputting sections. The busbar of the power integration allows the electric power inputted to the electric power inputting section to diverge to a plurality of the electric power outputting sections through a fuse and relay. The electric power outputting section of the busbar of the power integration is connected to various electronic instruments through a wiring harness.
In the electric junction box described above, the wiring block electrically connects the power source, electrical components, power integration, and electric wires of the wiring harness according to a predetermined pattern. The electric junction box supplies desired electric power to the respective electronic instruments through the wiring harness.
In the electric junction box described above, the electric power inputting section of the busbar of the power integration is connected to the terminal section of the wiring block through an electric wire. Such an electric wire tends to be thick because the electric power flowing therein is large.
Moreover, since various electronic instruments are mounted on the motor vehicle, the electric wires constituting the wiring harness tends to increase. Accordingly, demanded is an electric junction box which is capable of mounting various electronic instruments with high density mounting. Of course, a distance between the electric power inputting section of the busbar of the power integration and the terminal section of the wiring block tends to be small. As a result, in order to connect the electric power inputting section of the busbar of the power integration to the terminal section of the wiring block by using a relatively thick electric wire, so far, assembly of the electric junction box tends to be difficult because it is necessary to bend the thick electric wire within a narrow space.